US3342103A - Synchronizing unit for sound and still-picture presentation - Google Patents

Synchronizing unit for sound and still-picture presentation Download PDF

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Publication number
US3342103A
US3342103A US485237A US48523765A US3342103A US 3342103 A US3342103 A US 3342103A US 485237 A US485237 A US 485237A US 48523765 A US48523765 A US 48523765A US 3342103 A US3342103 A US 3342103A
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United States
Prior art keywords
slide
projector
switch
signal
voltage
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Expired - Lifetime
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US485237A
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English (en)
Inventor
William J Fabrey
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Eastman Kodak Co
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Eastman Kodak Co
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Priority to US485237A priority Critical patent/US3342103A/en
Priority to GB39275/66A priority patent/GB1158129A/en
Priority to DE1547264A priority patent/DE1547264C3/de
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B31/00—Associated working of cameras or projectors with sound-recording or sound-reproducing means
    • G03B31/06—Associated working of cameras or projectors with sound-recording or sound-reproducing means in which sound track is associated with successively-shown still pictures

Definitions

  • Arrangements of this general type are well known and normally comprise means for recording, along with the desired program material, a suitable control signal either on the same channel or on a separate channel from that used for the program material. This signal is then subsequently used to initiate a slide-changing operation of the projector.
  • control signal In those units arranged to record the control signal on the same channel as the audio program material, the control signal must, for practicable purposes, be of such a frequency and of such intensity that it is not particularly objectionable to those watching the program. Such apparatus, of course, also requires a frequency selective means for effectively sorting out the control signals from the program material itself. Units which utilize a dual-channel recorder, with the program material recorded on one channel and the control signals on the other, overcome this problem of sorting out the control signals from the program material, but they still require some means for generating the control signals in response to or simultaneously with a slide-changing operation.
  • a synchronizing unit which may be directly connected to a conventional slide projector and to a dual-channel tape recorder, without modification of either, and which is so arranged that it takes advantage of an AC. voltage pulse which is inherently present in the slide projector during a slidechanging operation, and utilizes this pulse as a control signal to be recorded on one channel of the tape recorder.
  • the unit further provides circuitry incorporating a relatively few readily available components, preferably including solid state components, which circuitry is responsive to such control signals during playback to effectively initiate a slide-changing operation of the projector.
  • FIG. 1 is a perspective View, somewhat diagrammatic in character, showing the synchronizing unit of my invention as it would be connected to a conventional slide projector and dual-channel tape recorder.
  • FIG. 2 is a schematic diagram showing the circuitry of my synchronizing unit as well as portions of the circuitry of the slide projector and remote control unit therefor and with which the synchronizing unit is to be utilized.
  • FIG. 1 there is shown a slide projector it provided with the usual adjustable projection lens assembly 11.
  • the projector is illustrated as being of the known type which utilizes a rotary slide tray 12 which, during slide-changing operations, is adapted to be rotated step by step to bring successive slides into projection position.
  • the projector is provided with the usual line cord 13, adapted to be connected to the conventional source of electrical power, an on-oif switch 14 being used to control the operation of the projector.
  • This projector is also provided with a remote control socket 15 to which a remote control unit 16 is adapted to be connected as by means of a cable 17 and plug 18.
  • My invention is preferably utilized in conjunction with a dual-channel tape recorder of conventional type, one channel of this recorder being used for recording and reproducing any desired program material and the other channel being utilized for recording and reproducing the slide-change signals. While applicant is describing the unit 20 as a tape recorder, it is to be understood that, as is customary, this unit is preferably arranged to both selectively record and reproduce any desired audio program or signal material on either or both channels.
  • the recorder 20 incorporates means (not shown) for feeding a recording tape 21, from a supply reel 22 past a dual-channel recording head 23 to a take-up reel 24.
  • such recorders normally incorporate a pair of internal speakers, one of which is shown at 25, and also a pair of audio output jacks 28 and 29, one for each channel, by means of which the audio outputs from the two channels may be connected to external amplifiers and/or speakers.
  • the tape recorder is conventionally provided with a line cord 30 for connection to the normal house current and with a function control knob 31 which controls the mode of operation of the recorder.
  • a microphone 32 or other source of program material, is connected by way of a cable 33 and plug 34 to the microphone input jack 27 of one of the channels of the recorder.
  • the remote control unit 16 is provided with a-suitable switch means 35 by selective operation of which the lens assembly 11 may be moved in or out to vary the focus, and also with a pair of push-button-actuated switches 36 and 37 to respectively control slide-changing actuation of the projector 10.
  • switch 36 When switch 36 is pushed, the slide carrier 12 will be rotated one step in the forward direction :and a particular slide will be automatically replaced by the next slide in the sequence.
  • Switch 37 on the other hand,
  • unit 80 is provided with a cable 81 and plug 82 adapted to mate with the remote control receptacle 15 of the projector 10. It also carries a socket 38, corresponding in contact arrangement with socket 15, and into which the plug 18 of the remote control unit 16 is adapted to be plugged.
  • the unit 80 also includes a cable 39 provided with a plug 40 which is adapted to be selectively inserted either into the microphone jack 26 of the recorder, during recording of program material, or into the speaker or output jack 28 of that channel during playback of the recorded material during a program presentation.
  • FIG. 2 there is shown at the left-hand 23 Q3 side of this figure so much of the circuitry of the slide projector 10 as is necessary to a proper understanding of the present invention. Similarly, at the right-hand side of this figure is shown the circuitry of the remote control unit 16 normally used with such a projector. Between the two is the circuitry of the synchronizing unit 84 As is shown in FIG.
  • the corresponding contacts of plug 32 and socket 38 of synchronizing unit 80 are directly connected to one another internally of the synchronizing unit by leads 41-44 respectively so that, even when the synchronizing unit is connected as described above, the remote control unit is operatively connected to the slide projector in exactly the same way that it would be if it were directly connected thereto by having plug 13 inserted directly into the socket 15 on the projector 10.
  • the slide-changing mechanism of the projector 10 is preferably of the type disclosed and claimed in the copending US. patent application of Robinson and Di Pietro, Ser. No. 336,034, filed May 8, 1964, now Patent No. 3,276,908. Reference may be made to the above application for a complete detailed description of such slidechanging mechanism. It will however suifice for the present case, to point out that this mechanism includes a solenoid 50, the energization of which trips a single revolution clutch (not shown) to release mechanical mean (not shown) which actually changes the slide and advances the slide tray.
  • the arrangement is such that if the solenoid 50 is energized but momentarily, the slide-changing mechanism will advance the tray in a forward direction relative to the normal slide sequence; if the solenoid 50 is held energized for an appreciably longer period of time, the movement of the slide carrier 12 and the resulting change of slides will be in the reverse sense.
  • the direction of advance of the slide tray is controlled by the selective operation of the forward switch 36 or the reverse switch 37 on the remote control unit 16.
  • Cur rent for energizing the solenoid 50 is supplied by the secondary winding 52 of a transformer 53, the primary 54 of which is connected by way of on-off switch 14 to the line cord 13, which as previously described is plugged into the usual supply of 120 volt, 60-cycle house current.
  • transformer 53 may be constituted by appropriate windings on a motor used for driving a cooling fan in the projector.
  • Leads 55 may be used to supply the other electrical apparatus incorporated in the projector 10, such as the usual projection lamp (not shown).
  • a normally-closed pair of contacts 56 are interposed between line 43, from forward switch 36, and solenoid 50.
  • switch contacts 56 are arranged to be opened by the act of tripping the one-revolution clutch upon energization of solenoid 50.
  • switch 36 is closed, a circuit will be completed by Way of line 44, switch 36, line 43 and switch contacts 56, to the solenoid 50 to energize the latter.
  • contacts 56 will open to deenergize the circuit through the solenoid. As previously explained this will result in a forward movement of the slide tray 12.
  • Projector also preferably incorporates a capacitor 58 shunting contacts 56 so as to prevent undue arcing thereof.
  • projector 10 is also preferably provided with a timer-controlled switch 59 which is effectively connected in parallel with the forward switch 36. As is evident from the drawing, when this switch is operated by suitable timing mechanism (not shown), a forward slide-changing operation will occur just as if switch 36 had been manually closed.
  • slide projector 10 is also provided with a remotely controllable focusing means.
  • focusing means may conveniently comprise a conventional D.C. type, polarity sensitive motor 60, the direction of rotation of which depends upon the polarity of the DC. current supplied thereto.
  • This motor is connected by suitable mechanical means (not shown) so as to move the lens assembly in or out, as the case may be.
  • switch means 35 is provided on the remote unit 16.
  • switch means 35 may conveniently comprise a pair of singlepole, double-throw switches 35a and 35b, with a rectifier 61 connected therebetween. Normally both switches are in the position shown in FIG. 2.
  • switch means 35 When switch means 35 is moved in one direction, it will reverse the contacts of switch section 35a, for example, so that a circuit will be completed from the transformer winding 52 through the normally closed contact of switch 35b, the diode rectifier 61, the switch section 35a, and line 41 to the focus motor 60, the polarity of the resulting pulsating voltage being such as to cause the focus motor to rotate in such direction as to move the lens assembly inward.
  • switch 35 If switch 35 is moved in the opposite direction, the diode 61 will be effectively inserted in this circuit in the opposite polarity direction, so that the effective direct current polarity of the voltage applied to focus motor 60 will be reversed, causing the latter to rotate in the direction to move the lens assembly outward.
  • a voltage divider 65 formed by a pair of resistors 66 and 67 of relatively high and low impedance respectively. It will be noted that this voltage divider is effectively in shunt with the contacts 56 in the projector, so that whenever these contacts 56 are opened, any voltage appearing thereacross will appear also across the voltage divider 65. That portion of such voltage which appears across the low impedance section 67 of the divider 65 serves as the slide-change signal which is to be recorded on the tape for future use for automatically initiating slide-change operations.
  • the junction 68 between resistors 66 and 67 and the grounded line 69 therefore serve as slide-change signal terminals.
  • terminals are connected by way of cable 39 to the previously mentioned plug 40 which, during recording, is inserted in the microphone jack 26 of the recorder 20.
  • the total impedance of voltage divider 65 should be sufficiently high that current flow therethrough will be below that needed to energize, or to hold energized, solenoid 50.
  • resistors 66 and 67 should be so chosen that the amplitude of the voltage appearing at the signal terminals will be within the normal recording range used with conventional tape recorders. I have found that a slide-change signal amplitude of approximately 30 millivolts is quite effective for this purpose.
  • the synchronizing unit 80 also includes circuitry which, when plug 40 is inserted in the audio output jack 28 of recorder and the latter is set for playback conditions, will respond to previously recorded slide-change pulses and initiate corresponding operation of the slide-change mechanism in the projector 10.
  • the synchronizing unit is provided with a silicon controlled rectifier 70, the anode 71 of which is connected to line 44 and the cathode 72 of which is connected to the grounded line 69.
  • the silicon controlled rectifier 70 is connected effectively in shunt with the forward control switch 36 of the remote control unit.
  • such silicon controlled rectifiers are normally nonconducting, but will be rendered conductive upon the application of a low positive potential to the control gate 73 of the rectifier. Once thus rendered conductive, the silicon controlled rectifier will continue to conduct until its anode voltage drops substantially to or below that on its cathode.
  • the terminal 68 of voltage divider 65 is connected through a diode 74 to a capacitor 75 so arranged that the latter will be charged up to approximately the positive peak value of the playback control signal.
  • the voltage on capacitor 75 charges up to the required triggering level for silicon controlled rectifier 70, the latter will be made conductive and will pass a half-wave-rectified or pulsating DC.
  • solenoid 50 by way of the circuit extending from one side of winding 52, line 44, silicon controlled rectifier 70, line 69, line 43, contacts 56, solenoid 50 and back to the other side of the winding 52.
  • This will energize solenoid 50, tripping the slide-changing which, as before, will cause the opening of contacts 56, interrupting this circuit.
  • solenoid 50 will once again be but momentarily energized and will accordingly cause the slide projector to change slides in the desired, forward direction.
  • the usual resistor 76 is connected from gate 73 of silicon controlled rectifier 70 to ground, to bleed off any charge thereon during non-conducting periods. This resistor also assures that capacitor 75 Will discharge promptly upon the termination of the signal pulse applied to terminal 68. Thus the voltage on the gate 73 of silicon controlled rectifier 70 will return to ground potential shortly after the termination of the reproduced control pulse, Well before the completion of the actual slide change cycle. 7
  • the latter is. preferably provided also with a thyrector 77 connected in parallel with silicon controlled rectifier 70; a capacitor 78, connected between lines 41 and 44; and a capacitor 79 connected between lines 42 and 43.
  • Thyrector 77 and capacitors 78 and 79 are for the purpose of protecting the silicon controlled rectifier against damage and for preventing the generation of false slide-changing signals, or triggering of the silicon controlled rectifier 70 due to switching transients such as may occur upon actuation of the focus control switch 35, for example.
  • the recorder in conjunction with the program tape 21, the recorder will be set for playback, the plug capacitor 79, have been found to be effective for this purpose.
  • the various resistors, capacitors, and solid state de-' vices used in the synchronizing unit are each relatively small in size and, as a result, the entire unit may be madeextremely small and compact. Moreover the components are relatively low-priced and readily available so that the unit itself may likewise be correspondingly low in price.
  • the slides will be arranged in the proper sequence in the slide tray 12 and the recorder 20 Will be set for recording.
  • the microphone 32 or other source of program material will be connected to the microphone input jack of one channel and the plug 40 of the synchronizing unit 80 will be inserted in the microphone jack of the other channel of the recorder.
  • the desired program material corresponding to each slide will thereupon be recorded simultaneously with the projection of that slide.
  • the operator desires to change slides he will press the forward slide-change button 36 to initiate a slide-changing operation.
  • a slide-change signal will 'be automatically produced at terminals 68, 69 of the synchronizing unit and will be applied through cable 39 and plug 40 to the recorder and be recorded on the signal channel of the tape 21. This operation will be repeated for each slide.
  • the synchronizing unit 80 in no Way affects the operation of the remote control unit.
  • the manual controls 36 and 37 may be used to independently control forward or reverse slide changes and the switch means 35 operated to focus the projector without any difficulty. It might also be mentioned that, during a recording session, only a forward slide-change will cause a slidechange signal to be recorded. No appreciable voltage appears across divider 65 at any time during a reverse slide-change operation under the control of reverse switch 37. 7
  • this invention provides an extremely simple, inexpensive, but nevertheless reliable means for correlating the operation of a conventional slide projector with that of a conventional tape recorder, and at the same time accomplishing this result without requiring any modification of either.
  • control circuit including a circuit component across which a voltage is developed during such operation of said mechanism
  • said connecting means including a voltage divider shunting said circuit component
  • electro-mechanical means responsive to a predetermined current fiow therethrough for initiating a slide-changing operation
  • an energizing circuit including a voltage source
  • said circuit including a normally closed pair of switch contacts in series with said electro-mechanical means
  • said contacts being arranged to be opened in response to initiation of a slide-changing operation by said means, to deenergize said circuit
  • slide-change signalling means comprising a pair of signal terminals
  • said energizing circuit including a normally open control switch for completing said circuit to initiate a slide-changing operation
  • said signal-controlled switch means being rendered conductive in response to a predetermined signal voltage at said signal terminals to initiate a slide-changing operation independently of said control switch.
  • electro-mechanical means responsive to a predetermined current flow therethrough for initiating a slide-changing operation
  • an energizing circuit including a source of cyclically varying voltage
  • said circuit including a normally closed pair of switch contacts in series with said electro-mechanical means
  • said contacts being arranged to be opened in response to initiation of a slide-changing operation by said means, to deenergize said circuit
  • control unit for correlating the operation of said slide projector and said recording apparatus
  • said unit comprising a pair of slide-change signal terminals
  • said means for connecting said signal terminals to said switch contacts including a relatively high impedance voltage divider connected in shunt with said contacts,
  • said signal terminals being connected across a relatively low-impedance portion of said divider.
  • electro-mechanical means operable upon energization thereof to initiate a slide-changing operation of said mechanism
  • an energizing circuit including a source of cyclically varying voltage
  • said switch and said contacts being connected in said circuit in series with said electro-mechanical means whereby respectively to control energization and deenergization of said electro-mechanical means
  • control unit for correlating the operation of said slide projector and said recording and reproducing apparatus
  • said unit comprising a pair of slide-change signal terminals
  • a norm-ally non-conductive, electrically-controlled switch means having control means operatively responsive to a predetermined signal voltage at said signal terminals to render said electrically-controlled switch means conductive
  • said electrically-controlled switch means comprising a silicon controlled rectifier having anode, cathode and control electrodes,
  • control electrode being responsive to said predetermined signal voltage to render the anodecathode path of said rectifier conductive.
  • the voltage from said source being alternating current voltage, whereby said controlled-rectifier upon being rendered conductive in response to said predetermined signal voltage will be restored to non-conductive condition during each alternating current cycle.
  • control electrode controlling the conductivity of said controlled rectifier in accordance with the potential across said capacitor.
  • a synchronizing unit for correlating the operation of a slide projector and a separate sound recording and reproducing apparatus comprising input, output, and signal terminals,
  • said signal terminals being connected across a predetermined portion of said Voltage divider, normally non-conducting, electrically-controlled switch means connected between said output terminals,
  • said switch means including a control element operatively responsive to a predetermined signal level at said signal terminals to render said switch means conductive
  • said switch means being a silicon controlled rectifier having its anode and cathode connected between said output terminals and including a control electrode constituting said control element,
  • said last mentioned connecting means includes a capacitor connected between said control electrode and said cathode
  • a synchronizing unit for correlating the operation (a) a slide projector of the type having electrically controllable slide-changing mechanism including a slide-change control switch for initiating a slidechanging operation thereof and a circuit component across which a voltage appears as a result of such initiation by said switch, and
  • said synchronizing unit being separate from both said projector and said sound apparatus and comprising:
  • normally non-conductive electrically-controlled switch means having a control element operative in response to a predetermined energization thereof to render said electrically-controlled switch means conductive
  • said unit will be effective to transmit a portion of the voltage appearing across the circuit component of such projector to such recorder for recording thereon as a slide-change signal
  • said unit will be responsive to the reproduction of previously recorded slide-change signals to render said electrically-controlled switch means conductive to initiate a slide-changing operation of said projector.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Projection Apparatus (AREA)
  • Signal Processing Not Specific To The Method Of Recording And Reproducing (AREA)
  • Television Signal Processing For Recording (AREA)
US485237A 1965-09-07 1965-09-07 Synchronizing unit for sound and still-picture presentation Expired - Lifetime US3342103A (en)

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Application Number Priority Date Filing Date Title
US485237A US3342103A (en) 1965-09-07 1965-09-07 Synchronizing unit for sound and still-picture presentation
GB39275/66A GB1158129A (en) 1965-09-07 1966-09-02 A Synchronizing Unit For A Slide Projection Apparatus
DE1547264A DE1547264C3 (de) 1965-09-07 1966-09-05 Dia-Steuergerät

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US485237A US3342103A (en) 1965-09-07 1965-09-07 Synchronizing unit for sound and still-picture presentation

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3504113A (en) * 1967-03-06 1970-03-31 Tnt Communications Inc Visual coordinating communication network
US3507571A (en) * 1967-04-03 1970-04-21 Walter F White Audio-visual apparatus
US3612675A (en) * 1969-12-10 1971-10-12 Gaf Corp Synchronizing circuit
US4165570A (en) * 1978-06-02 1979-08-28 Crancer Alfred Jr Pedestrian street and road crossing trainer and method
US4549796A (en) * 1983-07-22 1985-10-29 Hurvitz James S System for controlling the operation of a camera and projector
US4609268A (en) * 1980-04-30 1986-09-02 Cliff Crawford Visual presentation projection apparatus

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2975672A (en) * 1954-07-21 1961-03-21 Webster Electric Co Inc Combined tape recorder and film projector
US2985069A (en) * 1959-12-21 1961-05-23 Sidney O Sampson Audio visual synchronous recorder projector
US3026769A (en) * 1958-08-29 1962-03-27 Zeiss Ikon Ag Device for recording switching impulses
US3110216A (en) * 1960-03-23 1963-11-12 Norman L Chalfin Automatic slide projector program control
US3177767A (en) * 1961-02-01 1965-04-13 Armstrong Templeman Inc Electronic timed signalling device for use in a sound and picture projector
US3233510A (en) * 1962-09-19 1966-02-08 Robert H C Harrison Synchronizing means for slide projector and sound recorder
US3245156A (en) * 1963-09-23 1966-04-12 Northrop Corp Audio-visual display system

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2975672A (en) * 1954-07-21 1961-03-21 Webster Electric Co Inc Combined tape recorder and film projector
US3026769A (en) * 1958-08-29 1962-03-27 Zeiss Ikon Ag Device for recording switching impulses
US2985069A (en) * 1959-12-21 1961-05-23 Sidney O Sampson Audio visual synchronous recorder projector
US3110216A (en) * 1960-03-23 1963-11-12 Norman L Chalfin Automatic slide projector program control
US3177767A (en) * 1961-02-01 1965-04-13 Armstrong Templeman Inc Electronic timed signalling device for use in a sound and picture projector
US3233510A (en) * 1962-09-19 1966-02-08 Robert H C Harrison Synchronizing means for slide projector and sound recorder
US3245156A (en) * 1963-09-23 1966-04-12 Northrop Corp Audio-visual display system

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3504113A (en) * 1967-03-06 1970-03-31 Tnt Communications Inc Visual coordinating communication network
US3507571A (en) * 1967-04-03 1970-04-21 Walter F White Audio-visual apparatus
US3612675A (en) * 1969-12-10 1971-10-12 Gaf Corp Synchronizing circuit
US4165570A (en) * 1978-06-02 1979-08-28 Crancer Alfred Jr Pedestrian street and road crossing trainer and method
US4609268A (en) * 1980-04-30 1986-09-02 Cliff Crawford Visual presentation projection apparatus
US4549796A (en) * 1983-07-22 1985-10-29 Hurvitz James S System for controlling the operation of a camera and projector

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GB1158129A (en) 1969-07-16
DE1547264A1 (de) 1969-12-04
DE1547264C3 (de) 1975-03-20
DE1547264B2 (de) 1974-08-01

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